1. Field of the Invention
The present invention relates to a system and method for handling laser-communication multiplexing in chaotic secure communications, and more particularly, for decoding multiplex chaotic laser signals by utilizing a low-pass filter to increase the fractal dimension of the chaotic system, so that decoding of the multiplex messages encoded by chaotic behaviors can be achieved. The disclosure of the present invention can be applied to many kinds of secure communication systems.
2. Discussion of the Prior Art
The technique of multiplex transmission has been well established in the field of conventional laser communications. However, there is still no effective scheme for applying such laser multiplexing to chaotic secure communication systems. Moreover, although it is known that chaotic systems can be applied to secure communications, the conventional techniques of simplex-coupled synchronization can only work well in simplex transmission, and therefore difficulties arise in handling multiplex transmission. The main reason can be attributed to the nonlinear interaction among the multiplex laser signals, resulting in a superimposed, interfering and complex chaotic system. To resolve these two problems, a low-pass filter is utilized to increase the fractal dimension of the multiplex chaotic signals, so that the periodicity of these chaotic signals will be enhanced. This technique can be used to rebuild the multiplexed messages encoded by chaotic behaviors in laser communications.
It is an object of the present invention to provide a method for handling laser-communication multiplexing in chaotic secure communications. By using a low-pass filter, a chaotic time sequence of lower fractal dimension can be effectively increased to a chaotic time sequence of higher fractal dimensional, so that the periodicity of the multiplex signals will be enhanced and hence the decoding of messages from the chaotic laser signals become possible.
It is another object of the present invention to provide a method for handling laser-communication multiplexing in chaotic secure communications, wherein the scheme of chaotic secure communications utilizes the behavior of extremely sensitive dependence on initial conditions and the feature of randomness of the chaotic laser light.
It is another object of the present invention to provide a method for handling laser-communication multiplexing in chaotic secure communications, wherein the scheme of chaotic secure communications is achieved by adjusting the coupling parameters of the receiver system, so that the chaotic system of the receiver end is simplex coupled to the transmitter end, and thus prohibiting the transmitted messages to be rebuilt by any unauthorized receptor.